:after is not simply a class, but rather a pseudo-element used to inject content within the content of an element. To learn more about its functionality, you can refer to this resource.
By utilizing this pseudo-element, you have the ability to introduce additional space through CSS that was not originally defined in your HTML structure, mimicking the addition of another element inside the button.
For instance, take a look at the provided code snippet illustrating how the :after pseudo-element can be implemented:
.no_pseudo, .with_pseudo {
width:100px;
height:100px;
background:red;
margin:40px 0
}
.likeAfter {
background:blue;
width:50%;
margin:0 auto;
height:100%;
}
.with_pseudo {
position:relative;
}
.with_pseudo:after {
content:"";
position:absolute;
background:blue;
width:50%;
margin:0 auto;
height:100%;
left:0;
right:0;
}
<div class="no_pseudo">
<div class="likeAfter">
</div>
</div>
<div class="with_pseudo">
</div>
The above example demonstrates how the :after element functions as a child element nested within a div, achieved solely through CSS without altering the underlying HTML structure.
This particular method leverages :after with a specific styling attribute like background: #f1f1f1; and positioning relative to the button (margin-top:-120%). When the button is clicked, the style changes dynamically (margin:0), resulting in the desired effect alongside padding adjustments and opacity modifications.
An alternative approach can also be illustrated, as shown below:
.button {
position: relative;
background-color: #4CAF50;
border: none;
font-size: 28px;
color: #FFFFFF;
padding: 20px;
width: 200px;
text-align: center;
-webkit-transition-duration: 0.4s; /* Safari */
transition-duration: 0.4s;
text-decoration: none;
overflow: hidden;
cursor: pointer;
z-index:2;
}
.button:after {
content: "pseudo element >!<";
color:green;
background: #f1f1f1;
display: block;
position: absolute;
bottom:0;
left:0;
height:0%;
width:0%;
opacity: 0;
transition: all 3s;
}
.button:focus:after {
width:50%;
height:100%;
opacity: 1;
}
<button class="button">
I AM A BUTTON
</button>
In this scenario, the :after pseudo-element is positioned at the bottom-left corner of the button with initial styles set to width:0%;height:0%;opacity:0. Upon clicking the button, the styles transition to width:50%;height:100%;opacity:1, achieving the intended visual effect. Moreover, by including content:"" on the :after element, various elements or empty spaces can be inserted accordingly.
To delve deeper into the usage of both :before and :after pseudo-elements, additional information can be found here and here.
The concept of pseudo-elements may seem intricate, yet through this explanation, it aims to simplify their functionality and demonstrate how they contribute to generating dynamic effects. Should any queries arise, feel free to reach out for further clarification. Cheers!
REVISION POST-COMMENT :
1. The 'transition backwards' behavior occurs due to the :active state (:active). Once the button is activated, the :after gradually reverts back to its original state over a span of 15 seconds (as specified by transition:15s).
Similarly, the ripple effect operates similarly by transitioning between styles from opacity:0 to
opacity:1</code upon clicking, then returning to the initial state once the action completes.</p>
<p><strong>2.</strong> The use of <code>content:""
establishes space for the
:after or
:before pseudo-elements within the HTML structure.
Even when no textual content or images are embedded, employing content:"" is essential since it generates an empty placeholder crucial for the proper functioning of these pseudo-elements.
To elaborate further, two demonstrations showcasing the utilization of content:"" with both some content and no content are presented below:
h1:before {
content:"i am before < < < ";
font-size:14px;
color:red;
}
h1:after {
content:" > > > i am after";
font-size:14px;
color:blue;
}
h2:before {
content:"";
background:red;
width:20px;
height:20px;
position:absolute;
}
h2:after {
content:"";
background:blue;
width:20px;
height:20px;
position:absolute;
}
<h1>Text Before me </h1>
<h2>Just empty content </h2>